Cataracts have become one of the most common causes of visual impairment and blindness in our ageing population. Surgery is currently the only method of restoring vision to patients who have become visually impaired or blinded by cataracts.
Traditional cataract removal surgery requires the intact cataract-affected lens to be removed through a 7-10 mm incision formed in the anterior aspect of the lens capsule of the eye. After the in-tact cataract affected lens has been removed through the 7-10 mm incision, a prosthetic lens (e.g., a transparent lens formed of a biocompatable polymer) is then inserted through such 7-10 mm incision and implanted within the lens capsule to serve as a replacement for the previously-removed cataract-affected lens. These classic cataract removal procedures have proven to be successful in restoring vision, but often are associated with post-operative complications due to the large 7-10 mm incision formed in the lens capsule.
More recently, another surgical procedure, known as phacoemulsification, has been developed for removing cataract-affect lenses. In these phacoemulsification procedures, an ultrasonically vibrating probe is inserted into the lens capsule through an incision formed therein. The ultrasonically vibrating emulsification probe is then manipulated about to effect complete emulsification of the cataract-affected lens. The emulsified lens matter is then aspirated out of the lens capsule. Thereafter, the desired prosthetic lens replacement is inserted into the lens capsule. Although the diameter of the phacoemulsification probe may be relatively small, it is still typically necessary to utilize a capsular incision of 2.5-6.0 mm in length to allow the probe to be manipulated about sufficiently to accomplish complete emulsification and removal of the lens matter. Furthermore, it is often necessary to further enlarge the capsular incision through which the phacoemulsification probe was inserted to the usual 7-10 mm size to permit subsequent insertion of a preformed prosthetic lens implant into the lens capsule.
The need to form a relatively large incision in the anterior lens capsule to permit passage of a prosthetic lens replacement into the lens capsule may soon be obviated due to certain developments in the lens removal/replacement technology. For example, certain injectable lens replacement materials, known in the art and/or presently being developed, may be passed into the interior of the lens capsule through a needle or tubular cannula. Because these injectable lens replacement materials may be passed into the lens capsule through a relatively small opening, the advent of these injectable lens replacement materials may eliminate any need for the formation of large incisions in the lens capsule to allow a prosthetic lens to be inserted into the lens capsule.
Also, certain rotatable lens removing devices, such as those described in U.S. Pat. No. 5,437,678 (Sorensen) as well as in U.S. patent applications Ser. Nos. 08/421,421, and 08/658,846 may be inserted into the lens capsule through small (e.g., less than 3 mm) openings and may be held substantially stationary during lens reduction and removal, thereby avoiding any need for forming any large (e.g., greater than 3 mm) capsular incision.
In view of the development of modern injectable lens replacement materials and rotatable lens removing devices which may be inserted and operated through relatively small openings in the lens capsule, it is now possible to perform an entire cataract removal and prosthetic lens replacement, through a small (e.g., less than 3 mm) opening in the anterior lens capsule, while allowing the remainder of the anterior lens capsule to remain in-tact and unincised. However, the process of creating a small (e.g., less than 3 mm) opening in the anterior lens capsule is problematic due to the tendency of the lens capsule material to tear or "run" when punctured.
Accordingly, there presently exists a need for a new device capable of consistently making small (e.g., less than 3 mm) openings in the anterior lens capsule of the eye.